<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body> 
    <input class="btn" type="button"  value="播放" onclick="func()">
    
</body>
<script>
    let btn=document.querySelector('.btn')
    function func(){
        if(btn.value == "播放"){
            btn.value = "暂停"
        }else{
            btn.value = "播放"
        }
    }

</script>
</html>